Planets is absolutely free in support of the International Year of Astronomy 2009. Over 1.2 million downloads so far!
Is that dot, a star or a planet? Answer questions like this with "Planets". Discover when you can see a certain planet, and where to look for it in relation to the stars.
Provides lots of interesting information: location of the sun, moon, and planets in the sky maps of stars and constellations rise and set time of the sun, moon, and planets current and future moon phases 3D globe view of all planets and the moon facts sheet for each planet, including moon names